Pull-up latch mechanism have already been used in the prior art. Such known pull-up latch mechanism comprises:
a stator with a substantially cylindrical inner open channel having a longitudinal axis and extending from a front opening up to a back opening with a cross section smaller than the section of the front opening,
a cap attached to a cylinder (1), whereby the cylinder is adapted to be lodged into the open channel of the stator, when the cap is lodged at least partly into the front portion, whereby the cap and cylinder are adapted to rotate within the inner channel on the action of a control means,
a shaft (8) provided with a latching pawl and provided with a hole for receiving a rod, and
a control system comprising an outer sleeve and an inner sleeve provided each with a groove, said inner sleeve being inserted within the outer sleeve which is inserted within the inner channel of the stator through the front opening thereof.
a rod connects the shaft 8 with the said inner and outer sleeves, the end portions of the rod extending within the grooves of the said sleeves.
a system for connecting the outer sleeve with the cylinder.
Such systems are disclosed for example in GB2158866 and U.S. Pat. No. 7,441,427.
Drawbacks of such disclosed system is that inner and outer sleeves have to rotate with the channel of the stator, whereby increasing potential problem of gripping, as well as pivoting movements between the sleeves and/or with the shaft.
In such disclosed system there is no means for retaining the sleeves with the cylinder, as well as there is no means for maintaining the sleeve within the channel of the stator and/or for preventing some longitudinal movement of the sleeve in case the mechanism being in unlocked position.
In case of longitudinal movement of one or more sleeves, the shaft in unlocked position can also move longitudinal, whereby the latch can extend in a position preventing its rotation within a locked position.
EP1411198 disclose a latch mechanism comprising a drive input means arranged in a fixed housing, an output shaft connected to the drive input means. The output shaft is provided (a) with a L-shaped guide cam surface cooperating with a cam follower attached to the housing, and (b) an inclined cam surface cooperating with another cam follower pushed into a hole of an end of the drive input means, through a hole of the housing. In said mechanism, the drive input means is inserted into a sleeve of the output shaft, before inserting the drive input means and the output shaft within the axial passage of the housing through the back opening. Thereafter a guide pin has to be inserted through a lateral hole of the housing into the L shaped guide cam surface of the sleeve of the output shaft, so as to maintain the said sleeve into the housing. For the insertion of said cam follower, the sleeve and possibly the drive input means have to be correctly placed within the axial passage of the housing.
In such a mechanism, the cam follower acts as means for maintaining the sleeve into the passage of the housing, meaning that in case of excessive rotation of the sleeve, for example by a thieve, the cam follower can be broken off, whereby the sleeve can be pushed backwards, and whereby the mechanism is no more suitable to maintain locked a door, etc.
The mechanism of the invention aims to solve one or more of the problems listed hereabove.